Sub-surface bore hole gages



May 29, 1956 G. B. THOMAS ET AL 2,747,405

SUB-SURFACE BORE HOLE GAGES Filed 001;..10, 1951 5 Sheets-Sheet 2 GERALDB. YZ S A? James Moo/v INVENTORS.

HTTORNEY.

y 1956 G. B. THOMAS ET AL 2,7414% SUB-SURFACE BORE HOLE GAGES Filed Oct.10, 1951 5 Sheets-Sheet 4 33 %fi-- T M Pres s sureE-PSfiflNVENTORQflv-Toran/Ey,

2,747,405 SUB-SURFACE sans iron: GAGES GeraldlL Tlgomas, Los Angeles andJames Moon, Corona dcl Mar, Califg, assignors to Signal Oil and GasCompany, Los Angeles, Calif., a corporation of Delaware ApplicationOctober-10, 1951, semi No. 250,714 4 Claims. (Cl. is-345 Thisinventionrelates to a subsurface device for performing surveys in bore holesdrilled into the earth and more particularly in bore holes for theproduction of petroleum or gas from below the surface of the earth.

In all such prior art procedures, it is necessary to determine the depthat which the temperature of pressure recordis made. It has been thepractice to employ a clock in the instrument and to make the temperatureor pressure rccorda function of time by means of some sort of mechanicalconnection between the clock and the recording means. A trace is thusobtained which is a function of both tiine and temperature on the onehand or time and pressure on the other hand. The instrument is loweredinto the bore hole and a record is kept at the surface of therelationship of time to the amount of time passed in lowering theinstrument, so that time and depth are thus correlated.

In this procedure there is always an interval of time between thestarting of the clock and the start of the lowering process. This isoccasioned by the fact that the instrument must be in partlydisassembled condition when the clock is started, Then the instrument isassembled and introduced into the well, adjustments made, and thelowering started. Time is kept at the surface of the duration of thisprocedure and a correction must be made by measuring back on the recordthe recorded time, and, by interpolation on the record, determining thevalue of the recorded characteristics at the corrected timecorresponding to the depth recorded at the surface for such time.

Additionally, temperature in bore holes increases with depth, and thedriving mechanism connecting the clock and recording mechanism isaifected by such temperature and introduces an important error in therecordation of the time function in the instrument. 7 In other words,the clock record in the instrument is out ofstep with the clock recordat the surface so that it cannot be said with certainty that theinterval of time recorded by the clock in the instrument is the same asthat recorded by the clock at the surface.

In order to avoid such uncertainties, it is often the practice to stopthe descent of the instrument for a recorded period of time atsuccessive depths the value of which is known from surface measurements.Where the characteristics recorded change progressively with depth, thestopping of the instrument at a known depth for a short time willproduce a plateau in which such characteristics do not change with time.This will permit of a check on the depth measurement and or; correlationand correction of clock timing with depth. Thisprocedure has tliedisadvantage that it introduces an undesirable delay in the traverse.

In another method the instrument is lowered to a series of depths,measured by recording the amount of lowered line, and allowed to come torest at each depth so that equilibrium is established. No effort is madeto take the measurements between such depths. In other words,- the clockmerely acts to cause an advance of the chart that a trace can be made.The chart between the stopping United States Patent r 2,747,405 PatentedMay 29, 1956 2 point is ignored and since the number of stops made andthe corresponding depth at each succeeding stop is known, the actualdepth at each plateau is known and the magnitude of the recordedcharacteristic at each plateau may be measured from the chart.

It will be recognized that in order to make a deterrriiiiable plateau,at si nificant time interval must be al-' lowed ateach stop. This makesit impracticable, espec'ially in deep bores, to make the intervalbetween stops small so that frequently significant variations of thecharacteristics between stops are missed.

The correlation inetho'd has the difliculty arising from theindeterminacy of the effect of temperature on the clock mechanism or, inthe case of pressure measurement, on the pressure 'rec'or'dation, and inthe case of the step method the value of the characteristics between thestops is not obtained.

The pressure gages of the prior art are affected by temperature so thatit is necessary to calibrate the pressure gage for temperaturevariations. Thus pressures as measured by sub-surface gages are notaccurately determined unless they are corrected for sub-surfacetemperature at the point of measurement. Such temperature depends notonly on the geothermal gradient, but also upon such accidental factorsas entry of fluid into the bore hole, the velocity and quantity offluid, nature of fluid, and the mechanical condition of the bore hole atthe point of measurement. it is thus always necessary to estimate thetemperature at the point of measurement. The usual procedure is todetermine this from the known regional geothermal gradient. This, whilemore satisfactory in the case of a shut-in well, where thermalequilibrium is established, may, in a flowing well, give largelyerroneous results. It is thus necessary to make a separate thermometricsurvey to obtain accurate temperatures at the same depths as that atwhich the pressure is to be determined. This introduces anothertime-consuming operation.

One of us has devised an instrument which does not have thesedisadvantages. The said instrument is described and claimedinapplication Serial No. 127,181, new U. S. Patent 2,690,674.

we have devised a mechanism which obviates these difficulties andpermits a recordation of a mark which is correlatable with depth,temperature, and pressure without any substantial interruption of theprogress of the traverse. We have devised an instrument for measuringpressure and temperature simultaneously which avoids the abovedifiiculties. V I

Instead of employing the clock mechanism, weemploy in the invention ofthis application a temperature responsive device and a pressureresponsive device which are mounted in such manner that a simultaneousrecord of temperature, pressure, and depth is made. The instrumerit maybe lowered or raised in the bore hole at the desired rate to obtain acontinuous record under equilibrium conditions so that the trace of therecorded characteristies is a true record thereof throughout thetraverse of the instrument. We superimpos'e on such record a mark whichis correlatable with temperature, pressure, and depth, and does notrequire any recordation of the time interval involved. I u I I r In thepreferred embodiment of our invention we nt'roduce a motor means attestsfrom the surface in the preferred form of an inertially operated devicewhich actuate's a recording mechanism. In our preferred embodiment, weemploy a resiliently suspended mass, which may be the instrument or aportion thereof or a separately sus ended mass. By suddenly stopping,accelerating or decelerating the descent of the instrument, thevariation in acceleration actuates the inertial device so as to make amark. Since we may so stop, accelerate, or decelerate the device asfrequently as we wish and since the interval of descent during suchstoppage, acceleration or deceleration may be made as short as desiredor even reduced to zero, i. e., by stopping the instrument, we may makeas many such marks as we wish and thus obtain an accurate record of thevariations of the characteristics with depth and, of course, record thedepth, i. e., length of passedout line at each point of suchacceleration or deceleration.

in order to obtain these advantages we mount a thermomctric device inthe instrument to actuate a record making device so that the recordmaking device is actuated in proportion to the ambient temperature inthe bore hole at the place of measurement, and we also mount a pressureresponsive element in the bore hole and connect the same to actuate arecord making device in proportion to the pressure in the bore hole atthe location at which the measurement is to be made. Means are providedin the instrument to be actuated from the surface so that a mark is madeon the record which is correlatablc with depth. The result of thefunctioning of the thermometric pressure and inertial device is that wemay at any desired location in the bore hole produce a record which iscorrelatable simultaneously with the pressure, temperature, and at thelocation and correlatable with the depth at said location.

in a preferred embodiment we mount a chart holder which is actuated by athermometric motor and connect a marking system to a pressure bomb. Therelationship of parts is such that at any location of the instrument therelationship of the stylus, employed to mark the chart, to the chart isdetermined both by the temperature and by the pressure. It will beobserved that when such an instrument is lowered into the bore hole inwhich both temperature and/or pressure exist, the stylus will make aline trace the co-ordinates of which are pressure and temperature. in apreferred embodiment we mount the chart holder so that it is resilientlysuspended and may be inertially actuated by an alteration of theacceleration or" the instrument via the lowering line, so that when soactuated the chart holder bounces to cause the stylus to form adiscernible mark on the chart which is thus correlated with depth aswell as the temperature and pressure at the depth recorded.

The instrument is so constructed that it is possible, while lowering itin the bore hole, to maintain the instrument in equilibrium with itsenvironment so that the record will be a true measure of the magnitudeof gradient of pressure and of temperature throughout the bore hole.

Because, as is well known to those skilled in the art, the temperaturemay not be a continuous function of de th, due to local variations inthermal gradient, it is particularly desirable to have a continuoustrace of the actual variation of temperature. Our device permits of suchcontimtous trace of the temperature and the other recorded variable (e.g. pressure) function and the recording of the depth mark at closeintervals of the depth measurements.

This in ention is an improvement upon the construction of the device andwill also have the advantages inherent in the. device of saidapplication.

in our device the stylus is subjected to a compound motion over thechart. One element of the compound motion of the stylus is under theinfluence of the pressure responsive device and another of the elementsof said motion is under the influence of the temperature responsivedevice. The stylus is in marking relation to the chart in such mannerthat the trace of the stylus on the will be in a line, one coordinate ofwhich will be pressure and the other coordinate will be temperature.

This is accomplished by employing pressure and temperature resonsivedevices and a marking means, and suitable connections between themarking means and the temperature and pressure resonsive means of suchcharacter that the direction of motion of the marking means over thechart isperpendicular to the direction of motion of the stylusresponsive to pressure variations.

In order to introduce a third variable, i. e., the depth 2; at which anypressure and temperature are measured, we employ the expedient of theinertially actuated marking device invented by one of us and for whichapplications have been filed, Serial No. 72,450, January 24, 1949, nowU. S. Patent 2,690,673, and the above-mentioned Serial No. 127,181,filed November 14, 1949.

In the specific embodiment illustrated here, we suspend the chart holderon the inertial device in such manner that any sudden acceleration,upward or downward, will cause the chart to reciprocate vertically underthe stylus, thus mar 'ng a recognizable mark which will be correlatablewith depth.

Since the driving of the stylus introduces but a light load and sincethe stylus mechanism has a low inertia, the forces necessary to mark thechart are low. Thus it will take av much smaller force to drive thestylus than will be necessary to drive the chart mechanism in the priorart clock actuated devices. The error introduced by the oi the inertiaof the stylus is thus insignificant and an accurate response of thestylus to temperature and pressure is obtainable.

In the specific device, the stylus is moved over a relatively stationarycylindrical chart-holding member; the stylus is moved circumferentiallyover the chart under the influence of one of the variables and is movedaxially of the chart, i. e., parallel to the axis of the cylinder, overthe chart under the influence of the other of the variables. The stylusis mounted on a vertically reciprocable stylus rod which is reciprocatedby means of a bellows the extension of which is under the influence ofone of the variables. The stylus rod is also so mounted that it canrotate in any position of its vertical reciprocation, and the angularrotation is under the influence of a Bourdon tube so that the degree ofrotation of the rod is a function of the other of said variables.

Thus, for example, in the specific device illustrated, the Bourdon tubeis connected to a thermometric bulb and in the form of a thermometricmotor, i. e., a thermal responsive device for moving the stylus, and thebellows is connected to a flexible bulb the compression of which isobtained by the pressure of fluids in the bore hole and is thus in theform of a barometric motor, i. e., pressure responsive device for movingthe stylus. In this manner the longitudinal component (parallel to theaxis of the chart holder and chart) measures pressure, and thehorizontal component (along the circumference of the chart holder andthe chart) measures temperature. The reciprocation of the chart holderby actuation of the inertial marking device will cause an interruptionof the line formed by the tomperature-pressure trace which will be arecognizable record of depth.

Whereas in the prior description we have described our specific form ofthe combined pressure and temperature gage in which the pressureresponsive element causes an elevation of the stylus parallel to theaxis of the chart holder and the temperature responsive element causes aproportional rotation of the stylus about the axis, the motion may bereversed and the pressure responsive element causes a rotation of thestylus arm and stylus and the temperature responsive element a movementof the stylus parallel to the axis of the chart. This may beaccomplished by interchanging the barometric motor and the thermal motorconnections so that the Bourdon tube is connected to the barometricmotor and the bellows to the thermal motor.

To obtain these results in the instrument of the preferred embodiment ofour invention, we have devised and have assembled various elements intoa unitary wellcontained instrument, of which the following is a detaileddescription. In the drawings,

Figs. la, lb, and 1c are longitudinal views of section of the mechanismemployed and the manner in which they are assembled;

Fig. 2 is a section taken on the line 2-2 of Fig. la;

Fig. 3 is a partial vertical section taken on the line 3-3 of Fig. 2;

Fig. 4 is a section taken on the line 4-4 of Fig. Fig. 5 is a viewpartly in section illustrating the manner in which the inertial deviceis assembled with the inner sleeve plug;

Fig. 6 is a vertical view in section taken on the line 6-6 of Fig. 1a; pFig. 7 is a horizontal section taken on the line 7-7 of Fig. lb; V

Fig. 8 is a vertical section taken on the line 88 of Fig. 7;

Fig. 9 is a section taken on the line 9--9 of Fig. 10 and also Fig. lb;I I I Fig. 10 is a vertical section taken on the line 10-10 Fig. ll is asection taken on the line 11--11 Fig. 10; Fig. 12 is a hypotheticaltrace chart showing the markings produced by the stylus on the chartsheet; I

Fig. 13 is a vertical section taken on the line 13-13 of Figs. 14 and15; and also Fig. 1b; I I

Fig. 14 is a section taken on the line 14-14 of Fig. lb, alsoonFig. 13;I II I Fig. 15 is a section taken on the line 15-15 of Fig. 1b, alsoFig. 13. I p

In the drawings (see Figs la to 1c) the end piece 1 is provided with thelowering cable 1' and the screw-eye 2" is connected to the housing cap 2by means of the threaded connection 2'. The lower end of the housing cap2 is threaded and this threaded end is screwed into the upper end of theouter housing tube 3 which is closed at the lower end by being screwedonto the housing cap 2.

Within the housing tube 3 is nested varioiis units coinprising theinstrument in the following progressioni adjacent the housing cap 2 islocated the inner housing cap from which is suspended the inner housingtubular shell which is centered in housing cap 2 by the teat 4 whichenters the bore 3 in the lower end of the housing cap 2. Connected tothe inner housing cap 4 by means of the rods 5, made fast in the innerhousing plug 4, is the assembled inertial device 6. The inertial deviceis composed of a disk 5a, slotted at 55 to permitthe entry of the guidebar 7 mounted on the tubular wall 7'. The disk 5a is also provided witha slot 5c to permit the entry ofthe head 5d positioned at the top of therod se. The cylinder 6d is slidablyinourited on the rod 5a.. The top of6a is also slotted at 65 to permit the entry of the bar 7. Between theslotted portion 611 and the nut 5 screwedon the end of the rod 5c, ispositiened a spring 5g. The bottom of the cylinder 6a is closed by aplug 9 formed with a T- slot 9.1 into which the T-head 8a, mounted atthe top of the plug 8, passes. I I

The upper end of the plug 8 is attached to the tiibular, open-end hollowsleeve 10 which acts as the chart carrier. The sleeve 10 is suspendedbelow the inertial device 6 by means of the T-shaped top extension ofthe plug 8. I To the inner circumferential face of the sleeve ll)isattached the chart clamp 11 for receiving the chart on the inner faceof the chart holder. The chart ends are slipped underneath the clamp 11to hold the chart in position on the inner-surface 13 of the chartholder 10. I I

The lower face of the plug 8 is boreda't the center to receive the rod15 to which it ,is secured and this red acts as the stylus centeringmeans and telescopes inside the hollow tube 19. The stylus 14.isattached to the upper end of the stylus spring arm 16. The spring arrn16 is made fast at its lower end to the stylus lift arm collar 17mounted on the tu be 19. The centering spring 18 mounted on collar 17eiitends upwardly to assist in centering the collar 17. I I I I The liftarm collar 17 is made fast at the upperend of the stylus actuating tube19. The inner plug 20 is fast in the lower end of 19. This plug restsupon and is centered on a washer-shaped spring 21 which is locatedbetween the base of the tubular stylus arm guide 22 and the stylus armsupport 23. This arm suppert is made fast to the stylus actuating shaft24 by co I set screw 23'. This shaft 24 passes thrcugh an anti-frictionbear- 6 ing 25 located in the top of the housing coupling 3. The housingcoupling is bored to permit the passage of this rod tsee Figs. la and 6)j v The lower endof the housing coupling is threaded into a lowertubular outer housing 26. In this housing is located a Bourdon pressurecoiled tube 27 wound in spring-like fashion and this Bourdon tube isattached at its upper end to the collar 28 fixed on rod 24. The lowerend of the Bourdon tube is attached to the enlarged end 29 of the springhousing 31 (see Fig. 13). The stylus actuating shaft 24 is slidablymounted in upper collar 28 and continues downward through the center ofthe Bour-don tube coil. It is provided with a half-round groove 29a (seeFig. 8). A ball 29' located in the collar 28 projects into the groove29a and acts as a key in the shaft 24. The collar 28 is maintainedagainst vertical displacement by the ring 28' fast to the tube 2 6. Thislimits the motion of the Bourdon tube coil and the collar 28 ton rotarymotion, thus maintaining a fixedrotative relationship between the shaft24 and the collar 28. The groove 29a (see Figs. 1b and 8) extends fromabove the top collar 28 of the Bourdon tube, downward to a pointadjacent the base of the Bourdon tube.

Referring to Figs. 1a, 10 and 13, it will be seen that the adjacentdouble-walled, annular Sylphon bellows 33 surrounds the rod 24 which isconcentrically mounted inside the hollow core of the bellows. The guidetube 24 is mounted in the enlarged collar 29. The base of the bellows 33is connected to the enlarged end 29 of the spring housing 31. Thus eachof the lower ends of walls 33a and 33b may be brazed or soldered to theenlarged end 29.

At the top of the guide tube 24' is mounted the antifriction bearing 24ain which the rod 24 rotates. The tops of walls 33a and 33b of theSylphon bellows are clinched in the collar 36 to make a fluid-tightsealat the top of the annulus between the walls 33a and 33b, I A collar30a is pinned to the shaft 24 and is spaced from the collar 30b alsopinned tothe shaft 24. A plurality of circumferentially spaced jewelpins 30 are clamped in the collar 30 by means of the nut 33' against asuitably provided shoulder in the interior surfac e of 30. The collars30a and 30b will slide over the pins 30 when the collars are rotated bythe shaft 24, but the collars and the shaft are held against verticaldisplacement by the pins 30''.

I The shaft 24 eiitends downwardly through the guide tube 24 into theenlarged spring chamber 32 formed in the extension 38d of the outerhousing coupler 38 seerigs. la and 13). The lower end of the rod 24 isformed with a spring retaining shoulder 24a. The spring 32 is positionedaround the rod 24 and between the spring retaining shoulder 24a and theend of the spring chamber 32. A tube 36 passes through and is secured tothe upper enlarged end 29 and terminates in the annular space betweenthe bellows walls 33a and 33b. Thistube' 36 is part of the channel forthe passage of the fluid for transmitting pressure from the fluid filledflexible pressure bulb 41. I

A The housing coupling 38 is formed with a counterbore 44 at the topinto' which the tube 36 is secured by a fliiidtight joint and also withatapped counterbore 43 at the bottom and is provided with a channel 38'connecting the two counterbore's. The coupling is screwed into the tube415 into which also is received the connector 39. I The .counterhore 43at thebottom is threaded to receive the threaded piece 45 of theflexible pressure bulb 41 by afluid-tight connection. The bulb 41 ismounted in the chamber 41a which communicates with the space outside thetubular wall 41b of the chamber by means of port 41'. I

I A tube 46 (see Figs. 1c, 1b and. 13) is connected to the bottom of theBourdon tube 27 into which it opens and to which it is secured by afiuid tight joint. .The tube 46 extends down through the packing gland49" the coupling 49 and then passes downward to enter the coupling 49.The tube 46 is provided with the filling port 50 which, after thedesired filling has been accomplished, is then closed in any suitablemanner, such as with a plug 54) as shown or in any other suitablemanner.

The tube 46 is soldered or secured in any appropriate manner in thebottom of the tube coupling. It then continues downward through avertical bore 47 in the coupling 33 and thence through the bore 47 inthe cap 39. The lower end of the bore 4'7 is provided with packingretained in place by a packing gland 52. Below and contacting thepacking gland 52 is a packing washer 53 of insulating material throughwhich the temperature vapor tube 46 passes. The outside diameter of thewasher 53 is such that it contacts the inside wall of the dependingtubular bulb sleeve 54 which is screwed onto the lower end of the cap39.

A spacer sleeve 5'5 located inside the tubular bulb sleeve abuts at itsupper end the washer 53 and at its lower end contacts a screen 56 in theform of a dish; a short spacer 57 at its upper end abuts the screen 56and at its lower edge this spacer abuts the top edge of a closed-endtubular temperature bulb 58 screwed into the bulb sleeve 54.

The upper end of too temperature bulb 5? is screwed into the bulb sleeve54 until it presses all of the spacers and the interposed screen and thetop packing Washer 53 into their proper assembled leak-proof formation.

The temperature tube 46", after passing through the packing gland, andthe washer 53 containues downward through the center of the screen 56until the open bottom end of the tube 46 reaches a point adjacent theclosed end 59 of the temperature bulb 58.

it will thus be observed that the stylus arm is mounted coaxially withthe chart holder and is slidably responsive to pressure along the axisofthe chart holder under influence of expansion or contraction of thebellows 33 without any possibility of rotative movement when so moved,and that the expansion or contraction of the Bourdon tube induces arotary motion without introducing any axial movement, and that theinertial motor will move the chart in relation to the stylus withoutinfluencing the absolute position of the stylus with respect to the restof the system.

In operating the device, the instrument assembled as above is lowered onthe cable 1'. As it is lowered into the bore hole it entersprogressively zones of higher pressure. This pressure is exerted throughthe ports ill into the chamber 41a. The compression of the bulb 4iexerts fluid pressure which is communicated via tube 38, 33 (Fig. l3) tothe space between the walls 33a and 33b (Figs. 1 and 13). This causesthe sylphon bellows 33 to becomc extended. The collar 30 is thus liftedand this lift raises the pins 3-9 vertically lifting the rod 24. Indoing so the rod slides through the collar 23, the groove 29 passingover the ball 29' and the rod through the bear ing (Fig. 6). This liftcompresses the spring 32 (Fig.

13). it also lifts the stylus actuating tube 19 via the spring washer 21and this causes the stylus to travel over the chart mounted on the chartholder in a direction parallel to the axis of the rod, chart holder andinstrument. The rod is prevented from rotating by reason of the groove2% and ball 2," which permits axial, but not rotary, motion of the rod.Thus the rod and stylus move over the chart in a direction parallel tothe axis of the chart holder and in an amount proportionate to the pressure exerted in the chamber 41a.

The instrument also introduces a rotary motion of the stylus armproportionate to temperature. Thus the pressure of the fluid in the bulb58 is proportional to temperature and thus pressure is communicatedthrough the tube 4 47 (Fig. lc) 46 (Figs. 16 and 3) to the Bourdon tube2'7 The Bourdon tube 27 is connected to the collar 28 (Fig. .8). Thecollar is prevented from movement axially of the rod 24 on the Bourdontube 27 by reason of the ring 28' which is welded to the casing 26. Thuswhen the pressure in the Bourdon tube changes due to temperature changesat the bulb 53, the Bourdon tube cannot expand longitudinally and canonly change its dimensions radially by winding into a tighter or looserspiral. This causes the collar to rotate on its bearing. The ball 29 inthe groove 29 moves with the collar 23 introducing a rotary motion tothe rod 24.

This rotation because of the groove and ball combination may occur atany permissible vertical position of the rod 24 as it moves under theinfluence of the pressure exerted in the bulb 41. The rotation of therod 24 in its bearing 25 (see Fig. 6) causes the rotation of the stylustube 19 via the spring washer combination 21.

A rotation of the stylus arm is thus introduced circumferentially of thechart holder which is proportional to the temperature of the bulb 58.The stylus is thus moved over the chart mounted on the inner wall of thechart holder and a line is traced one coordinate of which is pressureand the other of which is temperature.

in order to introduce the depth variable in the chart the instrument isjarred. This may be accomplished by checking the ascent or descent ofthe instrument on its line or jiggling the line.

An accelerating or decelerating force is thus introduced into theinstrument, due to the inertia of the chart holder in which is suspendedon the spring 5g. This causes the cylinder 6 and the plug 3 and thechart holder to oscillate vertically. It is to be observed that thechart holder will not rotate due to the bar 7 b in the slots 5b.

This will introduce a jiggle in the chart which will be in the form of atrack or break parallel to the chart holder axis. Such a chart isillustrated in Fig. 12.

Fig. 12 gives the trace of an illustrative case of tem perature andpressure measured in the annulus outside the fluid-flow tube in an oilwell to illustrate the advantages of of the record made in theinstrument of our invention. The jiggles a to i, inclusive, for case I,are the markings caused by the initial marking device on the depthsindicated for the depths shown for such marking in Fig. 12. These depthsare recorded at the surface from the length of line 1 measured when therespective marks were made.

While we have described a particular embodiment of our invention for thepurpose of illustration, it should be understood that variousmodifications and adaptations thereof may be made within the spirit ofthe invention as set forth in the appended claims.

We claim:

1. A sub-surface temperature, pressure gage comprising a tubularhousing, a cylindrical chart holder mounted coaxially in the upper partof said tubular housing, a stylus in marking relation to said chartholder, a stylus supporting rod mounted axially of said tubular housing,an annular bellows mounted in said tubular housing, a collar, amechanical connection between said bellows and said collar for movementof said collar with said bellows axially of said chart holder, saidstylus support rod being rotatably mounted in said collar, a mechanicalconnec tion between said collar and said stylus support rod for movementof said stylus support rod with said collar axially of said chart holder21 barometric fluid motor mounted in said tubular housing, an operativefluid connection between said barometric motor and the annulus of saidannular bellows, a thermal fluid motor, said thermal fluid motorcomprising a Bourdon tube, a second collar, a mechanical connectionbetween said second collar and the end of said Bourdon tube, means forrotatably mounting said second collar in said tubular housing, said rodbeing slidably received in said second collar, means for restrictingsaid second collar against longitudinal movement axially of said rod,said rod having a keyway axially thereof, a key in said second collar,said keyway being adapted to travel along said key.

2. A sub-surface temperature, pressure gage comprising a tubularhousing, a cylindrical chart holder, a resilient suspension for saidchart holder, a support in said chart holder, a support in said tubularhousing for said resilient suspension, a stylus in marking relation tosaid chart holder, a stylus supporting rod mounted axially of saidtubular housing, an annular bellows mounted in said subular housing, acollar, a mechanical connection between said bellows and said collar formovement of said collar with said bellows axially of said chart holder,said stylus support rod being rotatably mounted in said collar, amechanical connection between said collar and said stylus support rodfor movement of said stylus support rod with said collar axially of saidchart holder, a barometric fluid motor mounted in said tubular housing,an operative fluid connection between said barometric motor and theannulus of said annular bellows, a thermal fluid motor, said thermalfluid motor comprising a Bourdon tube, a second collar, a mechanicalconnection between said second collar and the end of said Bourdon tube,means for rotatably mounting said second collar in said tubular housing,said rod being slidably received in said second collar, means forrestricting said second collar against longitudinal movement axially ofsaid rod, said rod having a keyway axially thereof, a key in said secondcollar, said keyway being adapted to travel along said key.

3. A sub-surface temperature and pressure gage comprising a tubularhousing, a cylindrical chart holder mounted in the upper part of andcoaxial with said tubular housing, a stylus in marking relation to saidchart holder, a stylus support mounted in said tubular housing, anannular bellows mounted in said tubular housing, a mechanical collarconnected to said annular bellows, a mechanical connection between saidcollar and said stylus support, said stylus support being rotatablymounted in said collar and fixed with respect to said collar againstaxial movement therethrough, a barometric fluid motor mounted in saidtubular housing, an operative fluid connection between said barometricfluid motor and the annulus of said annular bellows, a thermal fluidmotor positioned in said tubular housing, said thermal motor comprisinga Bourdon tube, a second collar, a rotary motion transmitting connectionbetween said second collar, and said stylus support, a mechanical motiontransmitting connection between said second collar and the end of saidBourdon tube, said support being fixed with respect to said secondcollar against rotary movement in said second collar, said support beingslidably received Within said second collar for axial movement thereinmeans for rotatably mounting said second collar in said tubular housing,and means for restraining said second collar against longitudinalmovement in said housing.

4. A sub-surface temperature and pressure gage comprising a tubularhousing, a cylindrical chart holder, a resilient suspension for saidchart holder, a support in said tubular housing for said resilientsuspension, a stylus in marking relation to said chart holder, anelongated stylus support mounted in said tubular housing, a barometricfluid motor in said housing, said motor including an annular bellows insaid housing, a collar, a mechanical motion transmitting connectionbetween said collar and the top of said bellows, a mechanical connectionbetween said collar and said stylus support for motion of said stylussuport and said collar along the axis of said support, said supportbeing rotatably mounted in said collar, a thermal fluid motor positionedin said tubular housing, said thermal motor comprising a Bourdon tube, asecond collar mounted on said stylus support, a mechanical connectionbetween said second collar and the end of said Bourdon tube, saidsupport being fixed with respect to said second collar against rotarymovement in said second collar, said support being slidably receivedWithin said second collar for axial movement therein means for rotatablymounting said second collar in said housing, and means for holding saidsecond collar against longitudinal movement in said housing.

References Cited in the file of this patent UNITED STATES PATENTS2,297,725 Spilhaus Oct 6, 1942 2,593,285 Fay et a1 Apr. 15, 19522,690,673 Thomas Oct. 5, 1954 2,690,674 Thomas Oct, 5, 1954

1. SUB-SURFACE TEMPERATURE, PRESSURE GAGE COMPRISING A TUBLUAR HOUSING,A CYLINDRICAL CHART HOLDER MOUNTED COAXIALLY IN THE UPPER PART OF SAIDTUBULAR HOUSING, A STYLUS IN MARKING RELATION TO SAID CHART HOLDER, ASTYLUS SUPPORTING ROD MOUNTED AXIALLY OF SAID TUBULAR HOUSING, A ANANNULAR BELLOWS MOUNTED IN SAID TUBULAR HOUSING, A COLLAR, A MECHANICALCONNECTION BETWEEN SAID BELLOWS AND SAID COLLAR FOR MOVEMENT OF SAIDCOLLAR WITH SAID BELLOWS AXIALLY OF SAID CHART HOLDER, SAID STYLUSSUPPORT ROD BEING ROTATABLY MOUNTED IN SAID COLLAR, A MECHANICOLCONNECTION BETWEEN SAID COLLAR AND SAID STYLUS SUPPORT ROD FOR MOVEMENTOF SAID STYLUS SUPPORT ROD WITH SAID COLLAR AXIALLY OF SAID CHART HOLDERA BAROMETRIC FLUID MOTOR MOUNTED IN SAID, TUBULAR HOUSING, AN OPERATIVEFLUID CONNECTION BETWEEN SAID BAROMETRIC MOTOR AND THE ANNULUS OF SAIDANNULAR BELLOWS, A THERMAL FLUID MOTOR, SAID THERMAL FLUID MOTORCOMPRISING A BOURDON TUBE, A SECOND COLLAR, A MECHANICAL CONNECTIONBETWEEN SAID SECOND COLLAR AND END OF SAID BOURDON TUBE, MEANS FORROTATABLY MOUNTING SAID SECOND COLLAR IN SAID TUBULAR HOUSING, SAID RODBEING SLIDABLY RECEIVED IN SAID SECOND COLLAR, MEANS FOR RESTRICTINGSAID SECOND COLLAR AGAINST LOGITUDINAL MOVEMENT AXIALLY OF ROD, SAID RODHAVING A KEYWAY AXIALLY THEREOF, A KEY IN SAID SECOND COLLAR, SAIDKEYWAY BEING ADAPTED TO TRAVEL ALONG SAID KEY.